Restricted TWT Fairness Through Early Service Period Termination

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Solution Overview

Problem

During restricted Target Wake Time (TWT) operation in wireless networks, channel under-utilization occurs when a station (STA) finishes transmitting latency-sensitive packets before the end of the service period, leading to inefficiencies, while allowing latency-tolerant traffic can create fairness issues among scheduled STAs.

Innovation Solution

Implementing methods and apparatuses for early termination of restricted TWT service periods based on buffer status reports and explicit signaling to balance channel utilization and fairness, ensuring STAs can transmit latency-tolerant traffic during remaining time, and allowing APs to terminate TWT sessions when all STAs have empty latency-sensitive buffers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If restricted TWT service period is extended to ensure latency-sensitive traffic transmission, then latency performance is improved, but channel utilization deteriorates when STAs finish transmission early

Engineering Contradiction:
ImprovelatencyVSAvoidchannel utilization
Core Design Contradiction:
Loss of timeVSProductivity

Solution Approach 1:

The service period duration is made dynamic rather than fixed. The AP monitors buffer status reports from STAs and adjusts the service period termination time accordingly. When all STAs report empty latency-sensitive buffers, the AP terminates the service period early, adapting the resource allocation to actual traffic needs and improving channel utilization.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements a feedback mechanism where STAs send buffer status reports to the AP during the service period. The AP uses this feedback information to make real-time decisions about service period termination, allowing it to respond to actual traffic conditions and optimize channel usage.

Inventive Principle:
Principle #23Feedback

2Productivity

If restricted TWT service period is shortened to improve channel utilization, then channel utilization is improved, but fairness among scheduled STAs deteriorates

Engineering Contradiction:
Improvechannel utilizationVSAvoidfairness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The AP continuously monitors buffer status reports from all scheduled STAs and uses this feedback to determine when to terminate the service period. This ensures that the service period continues long enough for all STAs to transmit their latency-sensitive traffic, maintaining fairness while avoiding unnecessary extensions that would harm channel utilization.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

STAs actively report their buffer status to the AP, enabling the system to make informed termination decisions. Each STA's self-reporting contributes to the collective determination of when the service period should end, ensuring fairness without requiring the AP to continuously poll all STAs.

Inventive Principle:
Principle #25Self-service

3Productivity

If restricted TWT service period is extended to allow latency-tolerant traffic transmission, then channel utilization is improved, but fairness among STAs deteriorates due to potential misuse by malicious STAs

Engineering Contradiction:
Improvechannel utilizationVSAvoidfairness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent separates latency-sensitive traffic handling from latency-tolerant traffic handling. By terminating the restricted TWT service period early when latency-sensitive traffic is complete, the system extracts and protects the fairness guarantee for latency-sensitive applications while allowing latency-tolerant traffic to use other channel access mechanisms.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system prevents potential fairness violations by malicious STAs before they can occur. By establishing clear termination criteria based on buffer status reports and terminating the service period when all STAs have finished latency-sensitive transmission, the system preemptively prevents any STA from abusing the extended period for unfair latency-tolerant traffic transmission.

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP4245071B1Fairness for restricted TWT operation
Publication Date: 2026.02.11 SAMSUNG ELECTRONICS CO LTD
  • EP4245071B1 patent drawingFigure 1
  • EP4245071B1 patent drawingFigure 2a
  • EP4245071B1 patent drawingFigure 2b

AI summary

Embodiments of the present disclosure provide methods and apparatuses for balancing a tradeoff between channel utilization and fairness during restricted target wake time (TWT) operation in a wireless network. The apparatuses include a wireless station (STA) device comprising a transceiver and a processor operably coupled to the transceiver. The transceiver is configured to transmit latency-sensitive uplink traffic and receive latency-sensitive downlink traffic in a restricted TWT service period (SP) during restricted TWT operation, and to receive, from an access point (AP), an indication that the restricted TWT SP is terminated early based on a lack of latency-sensitive uplink traffic for transmission by the STA and a lack of latency-sensitive downlink traffic for reception by the STA in a remainder of the restricted TWT SP. The processor is configured to terminate operation of the restricted TWT SP by the STA.